Roller Mill

Indian George

Well-Known Member
All the mills I have seen have belt and sprocket reductions. Any reasons, you couldn't use a motor with a speed controller???:s12138:a
 

rob45

Well-Known Member
I've been thinking about building a roller mill and have often wondered the same thing.
Essentially you're now talking about a direct drive?

I have no experience with the speed controllers; my grinders work with the stepped pulley arrangement.
I'm pretty ignorant concerning anything electronics; matter of fact, I'm just now learning how to wire a motor!
Never had a need to before because everything was always plug and play. Just goes to show that ignorance is not always bliss.:sad:

I've also wondered about using a gearbox as a reducer.

I think it comes down to accomplishing two objectives-enough torque and proper speed. Yet another issue is economics- which method is most economical yet still performs the job?

Speed (slowing it down enough) isn't the problem. This could be accomplished by your idea of speed-controlled motor, gearbox, sprockets, or even pulleys (although pulleys could slow it down enough, I scrapped that idea due to possible belt slipping issues- too bad, because I have a HUGE selection of big pulleys).

I have no idea what amount of torque is required for the rolling mill. I have heard that one of the advantages of the speed controllers is that torque is stabilized even at the lower speeds- I don't know enough about it.
If one could figure out how much torque is needed for this application, the motor (for a direct drive setup) could then be sized accordingly. Just guessing out of ignorance, but using a direct drive motor for this may need a bigger motor than our typical belt grinders. From what I gather, the controllers become exponentially expensive as the motor size increases. Again, I don't know enough about it to make the call.

But, something to take into consideration is that sprocket and gear arrangements have long been used to "amplify/increase" torque. I don't think it's a matter of increasing torque, but rather using the same amount of torque more efficiently. In other words, I think we are increasing leverage.
When you're riding a ten-speed bicycle and encounter a hill, you change gears (sprocket size) to make it easier to move the same weight (your body and the bike).
Your "motor" size (the strength of your body) does not change. The load (weight of your body and the bicycle) does not change either. But the work to be done is now "easier" because of a different sprocket size.

I'm certainly not an engineer of any type, so I do not understand the principles involved, but I have to wonder if the sprocket and chain setup is what allows us to use a "standard" motor on the roller mill.

I'll watch this thread with interest.

Robert
 

rob45

Well-Known Member
George,

I spent considerable time yesterday searching various forums, etc. for some info.

John Marcus (BF) was/is building units with a 115v, 1.5hp motor coupled to a gearbox (60:1). This has the gearbox directly coupled to the roller, so no chain-and-sprocket, and that arrangement made the entire unit more compact.

Another member over there is using a 3hp motor with a VFD, but still has it coupled to an altered gearbox, which is then attached to a chain drive.

I checked several different forums and websites; I could not find any instance where anyone was using a VFD motor directly coupled to the roller.

Good Luck,
Robert
 

12345678910

Well-Known Member
The vfd connected motors lose torque really quickly at very low speed.

If you read the manual for the KB vfd drives, there is a graph of that.

The vfd is good because it gives control over a wide speed range, but you don't need that high speed.

gearbox reducers and chain drives seem to be the way to go.

One build I looked at, the maker used a v belt drive to input into the gearbox, as he treated v belt slippage like a clutch to protect the gearbox and chain drive.
 
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busted knuckles

Well-Known Member
Many years ago I was the captain of a small tug boat. My boat and most other tugs used a wench (no, the other kind) with a planetary reduction gear and a relatively small hydraulic motor. if you are around any maritime industry, these wenches can be found cheap at a marine surplus yard. the planetary gear with an electric motor adapted to it might do the trick. or stay with the original hydraulic system.
 

Indian George

Well-Known Member
Many years ago I was the captain of a small tug boat. My boat and most other tugs used a wench (no, the other kind) with a planetary reduction gear and a relatively small hydraulic motor. if you are around any maritime industry, these wenches can be found cheap at a marine surplus yard. the planetary gear with an electric motor adapted to it might do the trick. or stay with the original hydraulic system.
Coooll idea:biggrin: I live in New Bedford, MA.:les: We have to biggest fishing fleet on the east coast.:yes: Got to check the junkyard.:les:
 

Jim Poling

Well-Known Member
Keith Johnson has a Roller Mill that is driven a motor/gear reducer drive and it works great. I know that he did all the welds on his tomahawks as well as some drawing with it. I have had opportunity to use it and I was impressed.

Jim
 

son of liberty

Well-Known Member
I have wrist pins from a huge international truck I rebuilt and wondered if they would make good roller mill rollers?

Dose anyone know what type of steel they are
 

rob45

Well-Known Member
Don't have any idea what type of steel your wrist pins are, but it may not matter as long as they are of approximate similar dimension to other successful units.

Several threads all over the net are discussing the various steels used, and many are successfully using mild steel for the rollers!:what!: Others are more comfortable using a tool steel, or maybe it could simply be a case of using whatever material happens to be available at the time.

The metal being rolled is hot, so maybe that's why we can get away with using even mild round stock.
Matter of fact, the size of the rollers is a key issue- going much larger than the plans call for seems to introduce more problems. The larger the roller, the greater the contact surface with the hot metal, which draws heat out (of the part being drawn) much quicker.
Bigger roller=less draws in one heat=more heats to finish part.
 

Jim Poling

Well-Known Member
your wrist pins will work fine once adapted to to work, I plan to use some heavy wall steel pipe I salvaged from a junked agricultural implant (Its still Green to).

Jim
 
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